# CVE-2026-12539

## Summary

- **CVE ID:** CVE-2026-12539
- **Severity:** MEDIUM
- **CVSS Score:** 5.1 (CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-923, CWE-665
- **Published:** Jun 18, 2026
- **Last Modified:** Aug 13, 2026

## Description

Docker Sandboxes (sbx) blocks ICMP egress with an authorizer applied only at network-creation time, and does not re-apply it to networks rebuilt from disk when the Docker daemon restarts, so a restart-surviving sandbox forwards ICMP to arbitrary hosts. A workload inside a sandbox, which the threat model treats as untrusted, can therefore defeat the documented ICMP egress block to perform network reconnaissance and exfiltrate data over an ICMP covert channel, regardless of the configured allowlist.

## Affected Products

- Docker — Docker Sandboxes (0.14.0)

## References

- [CNA](https://docs.docker.com/ai/sandboxes/)
- [CNA](https://github.com/docker/sbx-releases/releases/tag/v0.33.0)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.14%
- **EPSS Percentile:** 3.6

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._